FR3098780A1 - Autonomous driving system of a railway vehicle; railway vehicle and associated method - Google Patents

Abstract

Autonomous driving system for a railway vehicle; railway vehicle and associated method This system (10), on board a railway vehicle (1) and interfaced with a control/command unit (8) of the traction/braking means (3, 4) of the vehicle, comprises: means (21, 23, 33) for determining a position of the vehicle; means (25, 26, 39) for detecting an obstacle in a viewing region around the vehicle; a setpoint speed calculation means (37) for filtering each obstacle detected in the observation region by retaining only the detected obstacle located inside a monitoring zone, and for calculating a setpoint speed by depending on the position of the vehicle and the location of the obstacle inside the monitoring zone; and a speed regulation module (38) for generating, from the set speed, a set signal intended to be applied to the control/command unit (8). Figure for abstract: Figure 1

Description

Autonomous driving system for a railway vehicle; railway vehicle and associated method

The field of the invention is that of the autonomous driving of a railway vehicle, and more particularly of a tram.

In general, for driving a vehicle (car, bus, train, etc.) a reference autonomy scale has been defined which makes it possible to qualify the degree of autonomy with which the vehicle in question moves.

In this document, the level of autonomy sought is level “4” of this scale of autonomy. In level "4", the operation of accelerating, braking and steering of the vehicle is managed automatically, the operation of monitoring the environment in which the vehicle is moving is managed automatically, and the operation of reacting of the vehicle in the event of the occurrence of a problem (presence of an obstacle) is also managed by the vehicle. Level "4" differs from the highest level, level "5", in that the driving of the vehicle in autonomy is limited to certain predefined portions of road and not to all the roads on which the vehicle would have to travel. vehicle. It should be noted that level "0" of this autonomy scale corresponds to the case where all the preceding operations are carried out by the driver and level "1", in the case where the on-board system offers simple assistance to the driver of the vehicle for acceleration, braking and steering operation. Level “1” thus corresponds to driving assistance, commonly referred to as DAS for “ Driver Assistance System” .

It is desirable to be able to equip a tram with an autonomous driving system, at least on the sidings of the network on which it runs. It is therefore a question of managing the traction and braking of the tramway according to the environment of the tramway.

The object of the invention is therefore to solve this problem.

For this, the subject of the invention is an autonomous driving system for a railway vehicle traveling on a track, intended to be embarked on board said railway vehicle and interfaced with a control/command unit of the traction/braking means of the railway vehicle. , the autonomous driving system comprising:

- an acquisition means, suitable for determining a current position of the railway vehicle;

- an obstacle detection means capable of detecting and locating an obstacle in an observation region around the railway vehicle;

- a means of calculating the setpoint speed, clean:

in filtering the or each obstacle detected in the observation region by retaining only the or each detected obstacle which is located inside a surveillance zone, and,

calculating a setpoint speed as a function of the current position of the railway vehicle and the location of an obstacle located inside the monitoring zone; And

- a speed regulation module suitable for generating, from the set speed, a set signal intended to be applied to the control/command unit of the traction/braking means of the railway vehicle,

the surveillance zone being centered laterally on the track and having a width which is a function of a transverse gauge of the railway vehicle.

According to the invention, if the position of the tram along the tracks makes it possible to define a reference speed, the latter is modulated to take account of the presence of an obstacle only if it is in front of the tram. The system thus delivers a set speed to the speed regulation module controlling the traction/braking means of the tramway.

Such a system is therefore based on the ability to detect obstacles in front of the tramway along the track. Once the location of an obstacle has been determined, the system defines the reaction to adopt, in particular whether to activate the tram braking system and in what proportion.

According to particular embodiments, the autonomous driving system comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

- the surveillance zone corresponding to a portion of the observation region which follows the route of the track on which the railway vehicle is travelling;

- the surveillance zone extends over a predefined length from the front of the rail vehicle;

- the surveillance zone is equal to the width of the transverse gauge of the railway vehicle (1) increased by a distance of between 20 cm and 40 cm;

- a length of the surveillance zone is a function of an instantaneous speed of the rail vehicle;

- the surveillance zone is subdivided longitudinally into a plurality of domains, each domain being associated with an action to be implemented in the event of an obstacle located in said domain;

- the action associated with a domain is selected from: slowing down, braking and emergency braking; And,

- the implementation of the action consists in weighting a reference speed, which is determined according to the current position of the railway vehicle and a plan of the tracks, so as to obtain a setpoint speed adapted to the action to implement.

The invention also relates to a railway vehicle capable of being driven autonomously, carrying an autonomous driving system in accordance with the preceding system.

The invention also relates to a method for driving the preceding vehicle independently, characterized in that it comprises the steps consisting in: determining a current position of the railway vehicle; detecting and locating an obstacle in an observation region around the rail vehicle; calculate a setpoint speed by filtering the or each obstacle detected in the observation region by retaining only the or each detected obstacle which is located inside a monitoring zone, and by determining the setpoint speed as a function the current position of the rail vehicle and the location of an obstacle located inside the surveillance zone; and, regulate the speed by generating, from the set speed, a set signal intended to be applied to the control/command unit of the traction/braking means of the railway vehicle.

The invention and its advantages will be better understood on reading the following detailed description of a particular embodiment, given solely by way of non-limiting example, this description being made with reference to the appended drawings in which:

Figure 1 is a schematic representation of a tram equipped with an autonomous driving system according to the invention;

FIG. 2 is a functional representation in the form of blocks of the autonomous driving system of FIG. 1;

[Fig 4] [Fig 5] Figures 3 to 5 show, schematically, different areas to be monitored defined in front of the tram depending on the configuration of the track on which the tram of Figure 1 runs; And,

FIG. 6 is a schematic representation of an embodiment of the method according to the invention.

In Figure 1, there is shown a railway vehicle, in particular a tram 1 traveling on a track 2.

Conventionally, in order to be able to be driven by a driver, the tramway 1 comprises a chain for controlling the traction/braking means of the tramway, which are represented schematically in figure 1 by a motor 3 and brakes 4.

The control chain comprises, in the cabin, a manipulator 6 allowing the generation of setpoint signals. The joystick 6 has a pivoting stick which, when moved forward, allows the driver to request a traction effort and, when pivoted rearward, allows the driver to request a braking effort.

For example and preferably, the manipulator can be moved forwards in a first position corresponding to an increase of +50% of the effort in traction, or a second position of +15% of the effort in traction. It can be moved rearward into a first position corresponding to an increase of +50% in the braking effort, or a second position of +15% in the braking effort.

The setpoint signal generated by the manipulator 6 is applied as input to a unit 8 for controlling/commanding the traction/braking means. Unit 8 is able to control the traction/braking means by applying suitable control signals developed according to the setpoint signal received.

To be able to be driven independently according to level "4" of the scale commonly used for driving vehicles independently, tramway 1 is equipped with an autonomous driving system 10.

The system 10 is capable of generating setpoint signals of the same nature as those generated by the manipulator 6. In this way, the signals generated by the system 10 can be applied directly to the input of the control/command unit 8 replacing the setpoint signals generated by the manipulator 6.

Thus system 10 uses the existing control channel of unit 8 and unit 8 is unchanged from the state of the art.

To be able to switch from a driving mode with driver to an autonomous driving mode, the tram 1 is advantageously equipped with a two-state switch 12, making it possible to apply at the input of the unit 8 either a setpoint signal coming from the manipulator 6, or a setpoint signal coming from the system 10.

Advantageously, the state of switch 12 is controlled by a switch 14 placed in the cabin. Switch 14 is actuated by the driver, for example when tram 1 leaves a service track of the network to enter a siding of the network, a siding on which autonomous operation is authorised. Actuation of switch 14 leads to switching of switch 12.

System 10 includes a hardware layer shown in Figure 1.

The system 10 comprises, as acquisition means, a plurality of sensors connected to the input of a calculation unit 20.

Among the sensors used by the autonomous driving system 10, the tram is equipped with an inertial unit 21, suitable for determining an instantaneous vector acceleration of the tram and, by time integration, a first instantaneous speed of the tram.

The system also uses tachometric means 22, making it possible to determine a second instantaneous speed of the tramway 1 and, by time integration from a reference point along the track, the distance traveled by the tramway from this reference point and consequently a second current position of the tramway.

The sensors also include a sensor for a localization system capable of determining a first current position of the tramway. Preferably, in the embodiment presented here in detail, the sensor of the localization system is a LIDAR 23. The LIDAR 23 is a two-dimensional LIDAR having a high opening angle, for example 270°, and allowing, by processing the echoes received, to reconstruct the tram's environment and to obtain a reconstructed map. The plurality of sensors also comprises, more particularly for the obstacle detection function, a first LIDAR 25 and a second LIDAR 26.

The first LIDAR 25 is a three-dimensional LIDAR allowing the observation of a first region located in front of tramway 1.

The second LIDAR 26 is a two-dimensional LIDAR allowing the observation of a second region located in front of the tramway.

The cross-checking of the information delivered by the first and second LIDARs 25 and 26 allows the obstacle detection function to determine the relative position of an obstacle with respect to the front of the tramway within a region of extended observation.

Referring more particularly to figure 2, which takes up the various components of figure 1 but in a functional form, the system 10 will be presented in more detail, in particular the calculation unit 20.

The calculation unit 20 comprises a LIDAR localization module 33 able to take as input the signals delivered by the LIDAR 23 and to generate a reconstructed map as output. This reconstructed cartography is applied as input to a location module 32. The temporal evolution of the reconstructed environment also makes it possible to obtain information on the speed of the tramway, which is passed to a module 34 for estimating the speed of the tramway.

The module 34 for estimating the speed of the tramway, in addition to the speed at the output of the module 33, takes as input the signals delivered, on the one hand, by the inertial unit 21 and, on the other hand, by the tachometer means 22 .

The function of module 34 is to deliver an accurate estimate of the instantaneous speed of the tramway (V in FIG. 1).

This value of the speed delivered at the output of the module 34 is applied, on the one hand, to a speed regulation module 38 and, on the other hand, to the localization module 32.

The location module 32, in addition to estimating the instantaneous speed and the reconstructed cartography, takes as input the information delivered by the inertial unit 21. The function of the location module 32 is to deliver an accurate estimate of the instantaneous position of the tramway on the tracks.

In the embodiment presented here in detail, the module 32 is based on a map 31 of the region where the tramway 1 is authorized to circulate independently. This involves, for example, a mapping of the topology of the land (surface of the ground, buildings, permanently installed equipment, etc.) on which extend the garage tracks of the depot inside which the tram is running autonomy.

The location module 32 compares the environment reconstructed from the states received by the LIDAR 23 with the map 31 so as to determine a first current position of the tramway.

This first position is corrected from the information delivered by the sensors 21 and the integration over time of the speed delivered by the module 34.

The current position of tram 1 is applied to a mission management module 35 and to a speed calculation module 37.

The mission management module 35 is executed when the switch 12 is toggled to enable the autonomous driving mode.

The module 35 then acquires the current position of the tram to determine where the tram is on the rail network. Depending on this information and possibly other information communicated by a control center, a mission is assigned to tram 1. This mission may, for example, consist of indicating to system 10 whether tram 1 should park.

The speed calculation module 37 is suitable for defining a reference speed, depending in particular on the topology of the track on which tram 1 is running at the current time. Module 37 therefore defines the reference speed according to the current position of the tram and a plan of the tracks of the network.

For example, this reference speed is 10 km/h for a straight portion of track and 7 km/h for a curved portion of track or a portion of track approaching a switch.

Depending on the information delivered by the obstacle detection module 39, the speed calculation module weights the reference speed so as to deliver a set speed for the tramway 1. Indeed, if the obstacle detection module detects an obstacle in front of the tram, the reference speed must be reduced to avoid any collision.

The set speed, delivered by the module 37 is applied at the input of the module 38 for speed regulation. The latter, by comparing the set speed with the estimate of the current speed of the tramway delivered by the module 34, determines an appropriate tractive or braking force. The corresponding setpoint signal, of the same nature as that generated by the manipulator 6, is applied, via the switch 12, to the module 8 for control/command of the tram traction/braking means.

The module 39 is suitable for acquiring the signals delivered by the LIDARS 25 and 26.

Module 39 delivers, in the event of the presence of an obstacle inside the region observed by the LIDARS 25 and 26, the position of this obstacle in relation to the front of the tramway.

The operation of the system 10 in the event of detection of an obstacle by the module 39 and, more particularly, the way in which the speed calculation module 37 determines a set speed, will now be presented in relation to FIGS. 5 and the method of Figure 6.

Depending on the instantaneous position of tram 1, module 37 determines the type of track on which the tram is traveling at the current instant. To do this, the module 37 uses for example a plan of the track. The latter associates a type of track with each position of the tramway.

Three types of channel are for example predefined. These three types of channels are respectively represented in figures 3, 4 and 5.

The first type corresponds to a straight track section.

The second type corresponds to a curved track section.

Finally, the third type corresponds to a section of track approaching a switch.

Other channel types can be defined.

Recognition of the type of track on which the tramway is running enables module 37 to define the value of a reference speed. For example, the reference speed associated with the first type of track is 10 km/h; to the second type of 7 km/h; and the third type of 7 km/h.

Other reference speed values are possible.

Furthermore, module 37 defines, in front of the tramway, a surveillance zone within the observation region of module 39 for detecting obstacles.

The surveillance zone follows the route of the section of track in front of the tram. The determination of the type of the channel thus advantageously makes it possible to determine the geometry of the monitoring zone.

This surveillance zone is centered laterally on the track and has a width which depends on the transverse gauge of the tram, that is to say which extends laterally on either side of the track so as to correspond substantially to the transverse gauge of tram 1. For example, the width of the surveillance zone is equal to the overall width of the transverse gauge of tram (1) increased by a distance of between 20 cm and 40 cm.

The length of the surveillance zone depends on the current speed of the tramway.

The surveillance zone makes it possible to filter all the observations delivered by the module 39. Only the obstacles whose location falls within the surveillance zone will be retained.

Obstacles detected for module 39 but which are outside the surveillance zone will therefore have no impact on the operation of the tramway. This makes it possible to avoid untimely braking as soon as an object is detected in the tram's environment, even though there is no risk of collision with it.

As illustrated in figure 3, the monitoring zone Z1 for the first type of channel takes the form of a rectangle, while for the second type of channel, the monitoring zone Z2 takes the form of a portion of a torus. For the third type of track section and to maximize safety, the system does not take into account the switch engagement state. Consequently, the Z3 monitoring zone covers the two outgoing tracks of the switch.

Particularly advantageously, the monitoring area is subdivided into domains. For example, three domains are defined in the surveillance zone at any time.

Away from the tram, a first area, called a slowdown area, is defined. Then, closer to the tram and in continuity with the slowing down domain, a second domain, called braking. Finally, between the braking area and the front end of the tram, a third area, called emergency braking.

Thus, for example in FIG. 3, if an obstacle O is present in the slowdown domain D13 of the zone Z1, the module 37 calculates a setpoint speed such as to lead to a reduction in the instantaneous speed of the tramway. This can be done passively by using wheel/rail friction forces to gradually reduce the speed of the tram or by applying light braking.

If an obstacle is present in the braking range D12, the module 37 generates a setpoint speed leading to the tram stop at a minimum safety distance in front of the obstacle. This minimum safety distance is for example 1.2 m.

Finally, if an obstacle is detected in the emergency braking area D11, the module 37 delivers a setpoint speed leading to emergency braking to stop the tram over the shortest possible distance.

Similarly, in FIG. 4, the monitoring zone Z2 is subdivided into a slowing down domain D23, a braking domain D23 and an emergency braking domain D13.

In FIG. 5, for the case of a section of track approaching a switch, the monitoring zone Z3 is subdivided into a pair of slowdown domains D33 and D33' (each of these two domains being associated with one of the two outgoing lanes of the switch), a pair of braking domains D32 and D32' (each of these two domains being associated with one of the two outgoing lanes of the switch), and a braking domain emergency D31 (common to the two outgoing lanes of the switch).

It should be noted that figure 5 represents the surveillance zone as the tram enters the switch, the front of the tram being substantially in line with the switch. There is in fact a continuous evolution of the shape of the surveillance zone between that shown in Figures 3 and 4 and that shown in Figure 5 as a function of the distance from the tram to the switch.

In FIG. 6, the method implemented by the module 37 for calculating the setpoint speed is illustrated in the form of blocks.

At step 110, from the current position of the tramway and a plan of the rail network, the module 37 determines the type of track on which the tramway 1 runs.

In step 120, this information makes it possible to define the reference speed.

In step 130, a surveillance zone is defined at the front of the train. Advantageously, this monitoring zone is defined not only according to the type of track on which the tram runs, but also according to the speed of the tram. For example, the higher the tram speed, the greater the length of the surveillance zone.

The surveillance zone is subdivided into three domains, for example according to predefined proportions.

Finally, in step 140, the module 37 determines whether an obstacle is detected inside the surveillance zone. For this, it uses the obstacle location information determined by the module 39.

If no obstacle is located in the monitoring zone, the method loops back on itself and returns to step 110. The method 100 is thus iterated for each sampling period.

On the other hand, if, in step 140, an obstacle is detected, in step 150, the module 37 identifies the domain in which the obstacle is located.

At step 160, depending on the domain identified at step 150, the module 37 chooses an action to be carried out from among a slowing down of the tramway, a braking of the tramway or even an emergency braking.

At step 170, the corresponding speed setpoint is generated and applied to the speed regulation module 38.

If the obstacle was in the slowdown range, in step 180 the method loops to step 140 to determine the change in the position of the obstacle. Either the obstacle has left the monitoring zone and the method restarts at step 110, or the obstacle is still present and steps 150 and following are carried out again.

If in step 140, it had been decided to brake or emergency braking, at the end of step 170, one waits for the tram to come to a stop before carrying out the step 150 of verifying whether the obstacle has been moved out of the way. If so, the tram can restart. The method then loops back to step 110.

Claims (10)

Autonomous driving system (10) for a railway vehicle (1) traveling on a railway track (2), intended to be embarked on board said railway vehicle and interfaced with a control/command unit (8) of the traction means/ braking (3, 4) of the railway vehicle, the autonomous driving system (10) comprising:
- an acquisition means (21, 23, 33), capable of determining a current position of the railway vehicle;
- obstacle detection means (25, 26, 39) capable of detecting and locating an obstacle in an observation region around the railway vehicle (1);
- a setpoint speed calculation means (37), clean:
in filtering the or each obstacle detected in the observation region by retaining only the or each detected obstacle which is located inside a surveillance zone, and,
calculating a setpoint speed as a function of the current position of the railway vehicle and the location of an obstacle located inside the monitoring zone; And
- a speed regulation module (38) capable of generating, from the set speed, a set signal intended to be applied to the control/command unit (8) of the traction/braking means (3, 4) of the railway vehicle,
the surveillance zone being centered laterally on the track and having a width which is a function of a transverse gauge of the railway vehicle (1). System according to claim 1, in which the surveillance zone corresponds to a portion of the observation region which follows the route of the railway track (2) on which the railway vehicle (1) is traveling. System according to Claim 2, in which the surveillance zone extends over a predefined length from the front of the rail vehicle (1). System according to Claim 2 or Claim 3, in which the width of the surveillance zone is equal to the width of the transverse gauge of the railway vehicle (1) increased by a distance of between 20 cm and 40 cm. System according to any one of Claims 1 to 4, in which a length of the surveillance zone is a function of an instantaneous speed of the railway vehicle (1). System according to any one of Claims 1 to 5, in which the surveillance zone is subdivided longitudinally into a plurality of domains, each domain being associated with an action to be implemented in the event of detection of an obstacle in said domain. System according to claim 6, in which the action associated with a domain is selected among: a slowing down of the vehicle, a braking to stop the vehicle at a minimum distance from the detected obstacle and an emergency braking to stop the vehicle on a minimum distance. System according to any one of Claims 6 to 7, in which the implementation of the action consists in weighting a reference speed, which is determined as a function of the current position of the railway vehicle and of a plan of the tracks, so as to obtain a set speed adapted to the action to be implemented. Rail vehicle (1) capable of being driven independently, characterized in that it incorporates an autonomous driving system conforming to the system (10) according to any one of Claims 1 to 8. Method for driving a vehicle autonomously according to claim 9, characterized in that it comprises the steps consisting in:
- determining a current position of the railway vehicle;
- detecting and locating an obstacle in an observation region around the railway vehicle (1);
- calculating a target speed (37) by filtering the or each obstacle detected in the observation region by retaining only the or each detected obstacle which is located inside a monitoring zone, and by determining the speed as a function of the current position of the railway vehicle and the location of an obstacle located inside the monitoring zone; And,
- regulate the speed by generating, from the set speed, a set signal intended to be applied to the control/command unit (8) of the traction/braking means (3, 4) of the railway vehicle (1 ).